a(n) = (n^5 + 145*n^4 + 905*n^3 + 155*n^2 + 594*n + 120)/120.

Terms

a(0) =1a(1) =16a(2) =96a(3) =331a(4) =842a(5) =1782a(6) =3337a(7) =5727a(8) =9207a(9) =14068a(10) =20638a(11) =29283a(12) =40408a(13) =54458a(14) =71919a(15) =93319a(16) =119229a(17) =150264a(18) =187084a(19) =230395a(20) =280950a(21) =339550a(22) =407045a(23) =484335a(24) =572371a(25) =672156a(26) =784746a(27) =911251a(28) =1052836a(29) =1210722